Method of improving lifetime of etching liquid and yield in cu-interconnection process and cu-interconnection etching device

ABSTRACT

A Cu-interconnection etching device includes an etching liquid tank containing therein an etching liquid that is a hydrogen peroxide based solution, a first concentration monitoring device receiving the etching liquid from the etching liquid tank and measuring a copper ion concentration of the etching liquid. The etching liquid is supplied through a filter assembly that filters off copper ions contained in the etching liquid so as to provide a filtered etching liquid. The filter etching liquid is supplied through a second concentration monitoring device that measures a copper ion concentration of the filtered etching liquid and conducts the filtered etching liquid back to the etching liquid tank. A variation between the measurements of the first and second concentration monitoring devices is used to control the operation of the filter assembly in order to maintain a proper level of copper ion concentration in the etching liquid.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional application of co-pending U.S. patent applicationSer. No. 14/428,980, filed on Mar. 18, 2015.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of display technology, andmore particularly to a method of improving lifetime of etching liquidand yield in Cu-interconnection process and a Cu-interconnection etchingdevice.

2. The Related Arts

With the development of the display technology, flat panel devices, suchas liquid crystal displays (LCDs), possess advantages of high imagequality, power saving, thin body, and wide application scope. Thus, ithas been widely applied in various consumer electrical products, such asmobile phones, televisions, personal digital assistants, digitalcameras, notebook computers, and laptop computers, and become the majordisplay devices in the market.

Generally, a liquid crystal panel comprises a color filter substrate, anarray substrate, liquid crystal sandwiched between the color filtersubstrate and the array substrate, and sealant. Metal lines are formedon the array substrate. The resistance and RC delay due to theresistance of the metal lines have a great influence on the performanceof the liquid crystal display panel, and this is particularly obviousfor large scale and high resolution liquid crystal panels. The arraysubstrates of conventional liquid crystal panels commonly utilizealuminum (Al)-interconnection. The Al-interconnection has higherelectrical resistivity and the RC delay coming along therewith is alsolarger, making it hard to be applied to large scale and high resolutionliquid crystal display panels.

Compared with the Al-interconnection, Cu-interconnection possesses lowerelectrical resistivity and the RC delay coming along therewith issmaller, making it suit the needs for constant size growing up and highresolution of the liquid crystal display panels. However, in theconventional Cu-interconnection process, a hydrogen peroxide (H₂O₂)based solution is commonly utilized as an etching liquid. Such anetching liquid suffers certain problems. For example, the concentrationof copper ions in the etching liquid would increase with an increasednumber of substrates etched with such a liquid and H₂O₂ undergoes achemical change of increased speed of decomposition with the followingreaction process: H₂O₂-→H₂+O₂ with the presence of Cu ions. Furthermore,with the progress of the Cu-interconnection etching process, the copperion concentration of the etching liquid keeps increasing. Thedecomposition rate of the H₂O₂ gets faster and faster. When the copperion concentration exceeds 6000 ppm, the decomposition rate of the H₂O₂will rapidly increase and generates a mass of gas, which can causeexplosion of the apparatus. Therefore, as the copper ion concentrationexceeds 6000 ppm, new etching liquid has to be provided and used andthis greatly restricts the usage lifetime of the etching liquid andincreases the production cost. Besides, with the increase of the copperion concentration in the etching liquid, the etching rate of the etchingliquid will also change. Thus, the stability and the yield of productsare influenced.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a method ofimproving lifetime of etching liquid and yield in a Cu-interconnectionprocess, capable of adjusting the copper ion concentration of theetching liquid to promote the usage lifetime of the etching liquid andreduce the production cost for raising the stability and yield of theCu-interconnection production.

Another objective of the present invention is to provide aCu-interconnection etching device, capable of adjusting the copper ionconcentration of an etching liquid to promote the usage lifetime of theetching liquid and reduce the production cost for raising the stabilityand yield of the Cu-interconnection production.

For realizing the aforesaid objectives, the present invention firstprovides a method of improving lifetime of etching liquid and yield inCu-interconnection process, comprising the following steps:

step 1, providing an etching spray rising tank and an etching liquidtank connected to the etching spray rising tank, wherein the etchingliquid tank contains an etching liquid;

step 2, employing a first concentration monitoring device to measure acopper ion concentration of the etching liquid in the etching liquidtank, and employing a filter to perform copper ion filtering to theetching liquid in the etching liquid tank;

step 3, employing a second concentration monitoring device to measure acopper ion concentration of the etching liquid after filtering in step2, and controlling an amount of the filters employed to perform copperion filtering in step 2 and reflowing the etching liquid after filteringto the etching liquid tank.

The etching liquid employed in step 1 is a hydrogen peroxide basedetching liquid.

The filter in step 2 further comprises one or more reverse osmosismembranes connected in series for filtering copper ions, one or morefilter fabrics connected in series for filtering copper ions or severalreverse osmosis membranes and filter fabrics connected in series forfiltering copper ions.

The number of specific ones of the filters employed to perform copperion filtering is controlled to be activated by a control deviceaccording to a variation of the copper ion concentration of the etchingliquid measured by the first concentration monitoring device and thesecond concentration monitoring device and the filters are connected inseries.

The etching method of Cu-interconnection is employed for manufacturingan array substrate utilizing the Cu-interconnection. The firstconcentration monitoring device of step 2 further measures a hydrogenperoxide concentration and an additive concentration of the etchingliquid. The second concentration monitoring device of step 3 furthermeasures a hydrogen peroxide concentration and an additive concentrationof the etching liquid.

The present invention also provides a Cu-interconnection etching device,which comprises an etching spray rising tank, an etching liquid tankconnected to the etching spray rising tank, a liquid pump connected tothe etching liquid tank, and one or more filters connected to the liquidpump. The filter is connected to the etching liquid tank and comprises afirst concentration monitoring device for monitoring a copper ionconcentration of the etching liquid in the etching liquid tank.

The filter is employed to perform copper ion filtering to the etchingliquid to reduce the copper ion concentration of the etching liquid.

The first concentration monitoring device is located in the etchingliquid tank, between the etching liquid tank and the liquid pump, orbetween the liquid pump and the filter.

The Cu-interconnection etching device further comprises a secondconcentration monitoring device, and the second concentration monitoringdevice is located between the filter and the etching liquid tank andemployed to monitor a copper ion concentration of the etching liquidafter filtering. The first concentration monitoring device furthermonitors a hydrogen peroxide concentration and an additive concentrationof the etching liquid in the etching liquid tank. The secondconcentration monitoring device further monitors a hydrogen peroxideconcentration and an additive concentration of the etching liquid afterfiltering.

The number of the filters involved is plural and they are connected inseries. The Cu-interconnection etching device further comprises acontrol device, and the control device is electrically connected to thefirst concentration monitoring device, the second concentrationmonitoring device and each of the filters, to control whether each ofthe filter performs copper ion filtering or not according toconcentration monitoring result.

Each of filters further comprises one or more reverse osmosis membranesconnected in series for filtering copper ions, one or more filterfabrics connected in series for filtering copper ions, or severalreverse osmosis membranes and filter fabrics connected in series forfiltering copper ions.

The Cu-interconnection etching device is employed for a process of anarray substrate utilizing the Cu-interconnection.

The present invention further provides a method of improving lifetime ofetching liquid and yield in Cu-interconnection process, comprising thefollowing steps:

step 1, providing an etching spray rising tank and an etching liquidtank connected to the etching spray rising tank, wherein the etchingliquid tank contains etching liquid;

step 2, employing a first concentration monitoring device to measure acopper ion concentration of the etching liquid in the etching liquidtank, and employing a filter to perform copper ion filtering to theetching liquid in the etching liquid tank;

step 3, employing a second concentration monitoring device to measure acopper ion concentration of the etching liquid after filtering in step2, and controlling an amount of the filters employed in step 2 andreflowing the etching liquid after filtering to the etching liquid tank;

wherein the etching liquid employed in step 1 is a hydrogen peroxidebased etching liquid;

wherein the filter of step 2 further comprises one or more reverseosmosis membranes connected in series for filtering copper ions, one ormore filter fabrics connected in series for filtering copper ions, orseveral reverse osmosis membranes and filter fabrics connected in seriesfor filtering copper ions.

The benefits of the present invention are as follows. The presentinvention provides a method of improving lifetime of etching liquid andyield in Cu-interconnection process and a Cu-interconnection etchingdevice. By adding filters in a recycle process of the etching liquid toconstantly filter off copper ions of the etching liquid and reflowingthe etching liquid after filtering to the etching liquid tank for cyclicutilization, the copper ion concentration of the etching liquid can bereduced to promote the usage lifetime of the etching liquid and reducethe production cost for raising the stability and yield of theCu-interconnection production.

In order to better understand the characteristics and technical aspectof the invention, please refer to the following detailed description ofthe present invention is concerned with the diagrams, however, providereference to the accompanying drawings and description only and is notintended to be limiting of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The technical solution and the beneficial effects of the presentinvention are best understood from the following detailed descriptionwith reference to the accompanying figures and embodiments.

In the drawings:

FIG. 1 is a flowchart of an etching method of Cu-interconnectionaccording to the present invention; and

FIG. 2 is a structural diagram of an etching device ofCu-interconnection according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For better explaining the technical solution and the effect of thepresent invention, the present invention will be further described indetail with the accompanying drawings and the specific embodiments.

Referring to FIG. 1 in conjunction with FIG. 2, the present inventionfirst provides a method of improving lifetime of etching liquid andyield in Cu-interconnection process, which comprises the followingsteps:

step 1, providing an etching spray rising tank 1 and an etching liquidtank 2 connected to the etching spray rising tank 1, wherein the etchingliquid tank 2 contains an etching liquid.

Specifically, the etching liquid employed in the step 1 is a hydrogenperoxide based etching liquid.

step 2, employing a first concentration monitoring device 4 to measure acopper ion concentration of the etching liquid in the etching liquidtank 2, and employing a filter 5 to perform copper ion filtering to theetching liquid in the etching liquid tank 2.

Specifically, the filter 5 of step 2 further comprises one or morereverse osmosis membranes connected in series for filtering copper ions,one or more filter fabrics connected in series for filtering copperions, or several reverse osmosis membranes and filter fabrics connectedin series for filtering copper ions copper ions. In step 2, severalfilters 5 can be utilized, and the filters 5 are connected in series.Furthermore, a method of setting a cyclic tank can be employed tocollect the copper ions after filtering for recycling of the copperions.

The first concentration monitoring device 4 can be directly located inthe etching liquid tank 2, between the etching liquid tank 2 and theliquid pump 3, and respectively connected to the etching liquid tank 2and the liquid pump 3, or between the liquid pump 3 and the filter 5,and respectively connected to the liquid pump 3 and the filter 5, andcan be employed to monitor the copper ion concentration in the etchingliquid tank 2 in order to ensure a normal use of the etching liquid inthe etching liquid tank 2. Besides, the first concentration monitoringdevice 4 further measures a hydrogen peroxide concentration and anadditive concentration of the etching liquid for adding the additive intime to ensure the quality of the etching liquid and the etching resultof the Cu-interconnection.

step 3, employing a second concentration monitoring device to measure acopper ion concentration of the etching liquid after filtering in step2, and controlling a number of specific ones of the filters 5 to performcopper ion filtering in step 2 and reflowing the etching liquid afterfiltering to the etching liquid tank 2.

Specifically, in the step 3, the number of the specific ones of thefilters 5 employed to perform copper ion filtering is controlled to beactivated by a control device according to a variation of the copper ionconcentration of the etching liquid measured by the first concentrationmonitoring device 4 and the second concentration monitoring device 6. Ifthe copper ion concentration of the etching liquid after filtering islower than a demanded copper ion concentration of the etching liquid,the number of the filters 5 employed to perform copper ion filtering isdecreased. If the copper ion concentration of the etching liquid afterfiltering is higher than the demanded copper ion concentration of theetching liquid, the number of the filters 5 employed to perform copperion filtering is increased. Furthermore, the program can be set in thecontrol device to realize the automatic adjustment to maintain thecopper ion concentration at the best stable value.

The step 3 further comprises a step of measuring a hydrogen peroxideconcentration and an additive concentration of the etching liquid afterfiltering with the filter 5 by a second concentration monitoring device6, wherein the copper ion concentration of the etching liquid afterfiltering is monitored to ensure the filtering result and the hydrogenperoxide concentration and the additive concentration of the etchingliquid are monitored for adding the additive in time to ensure thequality of the etching liquid and the etching result of theCu-interconnection when the filter causes the additive concentrationloss.

At last, the Cu-interconnection etching method is employed formanufacturing an array substrate utilizing the Cu-interconnection.

Referring to FIG. 2, the present invention also provides aCu-interconnection etching device, which comprises an etching sprayrising tank 1, an etching liquid tank 2 connected to the etching sprayrising tank 1, a liquid pump 3 connected to the etching liquid tank 2,and one or more filters 5 connected to the liquid pump 3. The filter(s)5 are connected to the etching liquid tank 2 and further comprise afirst concentration monitoring device 4, which is employed to monitor acopper ion concentration of the etching liquid in the etching liquidtank 2. The filter(s) 5 are employed to perform copper ion filtering tothe etching liquid to reduce the copper ion concentration of the etchingliquid.

The first concentration monitoring device 4 can be directly located inthe etching liquid tank 2, between the etching liquid tank 2 and theliquid pump 3, and respectively connected to the etching liquid tank 2and the liquid pump 3, or between the liquid pump 3 and the filter 5,and respectively connected to the liquid pump 3 and the filter 5, andemployed to monitor the copper ion concentration in the etching liquidtank 2 in order to ensure a normal use of the etching liquid in theetching liquid tank 2. Besides, the first concentration monitoringdevice 4 further measures a hydrogen peroxide concentration and anadditive concentration of the etching liquid for adding the additive intime to ensure the quality of the etching liquid and the etching resultof the Cu-interconnection.

Particularly, the filter 5 is employed to filter the copper ions of theetching liquid to reduce the copper ion concentration of the etchingliquid. The filter 5 can be any device that filters off copper ions.Specifically, the filter 5 can comprise one or more reverse osmosismembranes connected in series for filtering copper ions to realize rapidcopper ion filtering. The reverse osmosis membranes can be regularlyreplaced according to the usage efficiency to ensure the filteringquality. Moreover, the filter 5 can comprise one or more filter fabricsconnected in series for filtering copper ions. The filter 5 also cancomprise several reverse osmosis membranes and filter fabrics connectedin series for filtering copper ions. Besides, the filter 5 can furthercomprise a cyclic tank (not shown), which is employed to collect thefiltered copper ions after filtering for recycling of the copper ions.

The Cu-interconnection etching device further comprises a secondconcentration monitoring device 6, and the second concentrationmonitoring device 6 is connected to the filter 5 and the etching liquidtank 2 to monitor the copper ion concentration of the etching liquidafter filtering to ensure the filtering result. Meanwhile, the secondconcentration monitoring device 6 can further monitor a hydrogenperoxide concentration and an additive concentration of the etchingliquid for adding the additive in time according to the monitor datawhen the filter 5 causes the additive concentration loss.

Besides, the number of the filters 5 can be increased or decreasedaccording to the copper ion concentration demand of the etching process.Preferably, the Cu-interconnection etching device further comprises acontrol device, and the control device is electrically connected to thefirst concentration monitoring device 4, the second concentrationmonitoring device 6, and each filter 5 to control whether each filter 5performs copper ion filtering or not according to concentrationmonitoring result. Specifically, the control device obtains the copperion concentration data of the etching liquid before filtering from thefirst concentration monitoring device 4, and obtains the copper ionconcentration data of the etching liquid after filtering from the secondconcentration monitoring device 6, and monitors whether the filteringresult reaches a target or not according to a variation of the copperion concentration of the etching liquid before and after filtering andthe copper ion concentration data of the etching liquid demanded by theetching process. If the copper ion concentration of the etching liquidafter filtering is lower than the demanded copper ion concentration ofthe etching liquid, the number of the filters 5 employed to performcopper ion filtering is decreased. If the copper ion concentration ofthe etching liquid after filtering is higher than the demanded copperion concentration of the etching liquid, the number of the filters 5employed to perform copper ion filtering is increased. Thus, real-timeadjustment of the copper ion concentration of the etching liquid can beachieved. Furthermore, the program can be set in the control device torealize the automatic adjustment to maintain the copper ionconcentration at the best stable value.

At last, the Cu-interconnection etching device is employed for a processof an array substrate utilizing the Cu-interconnection.

In conclusion, the present invention provides a method of improvinglifetime of etching liquid and yield in Cu-interconnection process and aCu-interconnection etching device. By adding filters in a recycleprocess of an etching liquid to constantly filter copper ions of theetching liquid and reflowing the etching liquid after filtering to theetching liquid tank for cyclic utilization, the copper ion concentrationof the etching liquid can be reduced to promote the usage lifetime ofthe etching liquid and reduce the production cost for raising thestability and product yield of the Cu-interconnection production.

The above provides only specific embodiments of the present invention,and the scope of the present invention is not limited to suchembodiments. Those skilled in the art would appreciate change orreplacement, which can be easily derived from the above, should becovered by a protection scope of the invention. Thus, the protectionscope of the invention should be defined by the appended claims.

What is claimed is:
 1. A Cu-interconnection etching device, comprising:an etching liquid tank containing therein an etching liquid; a firstconcentration monitoring device that measures a copper ion concentrationof the etching liquid in the etching liquid tank and operating a filterassembly arranged downstream the etching liquid tank to receive theetching liquid from the etching liquid tank and filtering copper ionsfrom the etching liquid received thereby so as to provide a filteredetching liquid; and a second concentration monitoring device that isarranged downstream the filter assembly to measure a copper ionconcentration of the filtered etching liquid and conducts the filteredetching liquid back to the etching liquid tank, wherein the firstconcentration monitoring device provides a first measurement of copperion concentration of the etching liquid that is measured upstream thefilter and the second concentration monitoring device provides a secondmeasurement of copper ion concentration of the filtered etching liquidthat is measured downstream the filter and a variation between the firstand second measurements is applied to control the operation of thefilter assembly for filtering copper ions from the etching liquidreceived from the etching liquid tank.
 2. The Cu-interconnection etchingdevice as claimed in claim 1 further comprising a liquid pump connectedto the etching liquid tank and the filter assembly is connected to theliquid pump to allow the liquid pump to supply the etching liquid fromthe etching liquid tank to the filter assembly via the firstconcentration monitoring device.
 3. The Cu-interconnection etchingdevice as claimed in claim 2, wherein the first concentration monitoringdevice is arranged in the etching liquid tank and located between theetching liquid tank and the liquid pump or between the liquid pump andthe filter assembly.
 4. The Cu-interconnection etching device as claimedin claim 1, wherein the second concentration monitoring device islocated between the filter assembly and the etching liquid tank.
 5. TheCu-interconnection etching device as claimed in claim 1, wherein theetching liquid comprises a hydrogen peroxide based solution.
 6. TheCu-interconnection etching device as claimed in claim 5, wherein thefirst concentration monitoring device further monitors a concentrationof hydrogen peroxide of the etching liquid received from the etchingliquid tank and the second concentration monitoring device furthermonitors a concentration of hydrogen peroxide of the filtered etchingliquid.
 7. The Cu-interconnection etching device as claimed in claim 5,wherein the etching liquid comprises a hydrogen peroxide based solutionand an additive.
 8. The Cu-interconnection etching device as claimed inclaim 7, wherein the first concentration monitoring device furthermonitors a concentration of hydrogen peroxide and a concentration of theadditive of the etching liquid received from the etching liquid tank andthe second concentration monitoring device further monitors aconcentration of hydrogen peroxide and a concentration of the additiveof the filtered etching liquid.
 9. The Cu-interconnection etching deviceas claimed in claim 1, wherein the filter assembly comprises one filter.10. The Cu-interconnection etching device as claimed in claim 1, whereinthe filter assembly comprises a plurality of filters connected in seriesand the control of the operation of the filter assembly comprisesselectively activating a specific number of filters among the pluralityof filters while keeping a remaining number of filters of the pluralityof filters deactivated, wherein the specific number is determinedaccording to the variation between the first and second measurements.11. The Cu-interconnection etching device as claimed in claim 10,wherein each of the filters comprises one or more reverse osmosismembranes connected in series.
 12. The Cu-interconnection etching deviceas claimed in claim 10, wherein each of the filters comprises one ormore filter fabrics connected in series.
 13. The Cu-interconnectionetching device as claimed in claim 10, wherein each of the filterscomprises multiple reverse osmosis membranes and multiple filter fabricsconnected in series.
 14. The Cu-interconnection etching device asclaimed in claim 9, wherein the filter comprises one or more reverseosmosis membranes connected in series.
 15. The Cu-interconnectionetching device as claimed in claim 9, wherein the filter comprises oneor more filter fabrics connected in series.
 16. The Cu-interconnectionetching device as claimed in claim 9, wherein the filter comprisesmultiple reverse osmosis membranes and multiple filter fabrics connectedin series.
 17. A Cu-interconnection etching device, comprising: anetching liquid tank containing therein an etching liquid; a firstconcentration monitoring device that measures a copper ion concentrationof the etching liquid in the etching liquid tank and operating a filterassembly arranged downstream the etching liquid tank to receive theetching liquid from the etching liquid tank and filtering copper ionsfrom the etching liquid received thereby so as to provide a filteredetching liquid; and a second concentration monitoring device that isarranged downstream the filter assembly to measure a copper ionconcentration of the filtered etching liquid and conducts the filteredetching liquid back to the etching liquid tank, wherein the firstconcentration monitoring device provides a first measurement of copperion concentration of the etching liquid that is measured upstream thefilter and the second concentration monitoring device provides a secondmeasurement of copper ion concentration of the filtered etching liquidthat is measured downstream the filter and a variation between the firstand second measurements is applied to control the operation of thefilter assembly for filtering copper ions from the etching liquidreceived from the etching liquid tank; and wherein the filter assemblycomprises a plurality of filters connected in series and the control ofthe operation of the filter assembly comprises selectively activating aspecific number of filters among the plurality of filters while keepinga remaining number of filters of the plurality of filters deactivated,wherein the specific number is determined according to the variationbetween the first and second measurements.
 18. The Cu-interconnectionetching device as claimed in claim 17, wherein each of the filterscomprises one or more reverse osmosis membranes connected in series. 19.The Cu-interconnection etching device as claimed in claim 17, whereineach of the filters comprises one or more filter fabrics connected inseries.
 20. The Cu-interconnection etching device as claimed in claim17, wherein each of the filters comprises multiple reverse osmosismembranes and multiple filter fabrics connected in series.